The present invention pertains to receivers, and more particularly to a system and method for receiving analog and digital signals that results in lower power consumption than known systems and methods for receiving analog and digital signals.
Dual mode receivers for cellular handsets are known in the art. Such dual mode receivers are typically used to process a signal that may be encoded using an analog format, such as the Advanced Mobile Phone Service (AMPS) format, or in a digital format, such as a code division multiple access (CDMA) or Personal Communications Services (PCS) format. The dual mode receivers allow a cellular telephone handset to receive signals in a variety of formats, thus allowing different service providers to use the same cellular handsets. In addition, the same cellular handset may be used in areas that provide service according to different formats, such that users may roam outside of a service area of their service provider and may still use the cellular services of another service provider.
Although such dual mode receivers are known, they suffer various drawbacks and shortcomings. In order to allow analog or digital format signals to be processed, it is necessary to either provide completely separate receivers, or to process analog encoded signals using the digital signal processing systems and components that are used for digitally-encoded signals. Such digital processing of analog signals requires significantly greater power than processing of digital signals, which results in increased battery power consumption. Likewise, providing separate digital and analog receiver chains duplicates many components, which also increases power consumption. In addition, dual receiver chains increases the cost of the receiver, the weight of the receiver, and the size of the receiver.
In accordance with the present invention, a system and method for receiving a signal are provided that overcome the problems and deficiencies of known systems and methods for receiving a signal.
In particular, a system and method for receiving a signal are provided that allow analog encoded signals to be decoded using analog systems and components, and digitally-encoded signals to be decoded using digital systems and components, so as to optimize the power required to demodulate the signal, regardless of the type of signal received.
In accordance with an exemplary embodiment of the present invention, a system for receiving a transmitted signal is provided. The system includes a first receiver that can receive the transmitted signal and decode the transmitted signal according to a first demodulation format, such as a CDMA or PCS format. A second receiver, such as an FM demodulator, is connected to the first receiver at a suitable location, such as after initial signal amplification and processing has been completed. The second receiver can decode the transmitted signal according to a second demodulation format, such as AMPS.
The present invention provides numerous important technical advantages. One important technical advantage of the present invention is a system for receiving a signal that may be encoded in an analog format or a digital format that allows conventional analog systems and components to be used to demodulate and process analog signals. The present invention thus eliminates the need to process analog encoded signals using digital signal processing systems and components, which may require increased amounts of power to process analog encoded signals as compared with digitally encoded signals.